C++ deep_learning [feedForward] identity functions

#include <iostream>
using namespace std;
class Neuron
{
public:
    double w_;
    double b_;

    double getAct(const double& x)
    {
        return x;
    }
    double FeedForward(const double& input)
    {
        const double sigma = w_ * input + b_;
        getAct(sigma);
    }
};
int main()
{
    Neuron my_neuron;
    my_neuron.w_ = 2.0;
    my_neuron.b_ = 1.0;
    cout << "input = 1.0" << '\n'  << my_neuron.FeedForward(1.0) << endl;
    return 0; 
}